Mechanical Activation Research Articles

Impact of gradient microstructure on strain hardening via activation of multiple deformation mechanisms in CoCrNi medium entropy alloy

Abstract Face centered cubic (FCC) structural medium/high entropy alloys (MEAs), characterized by excellent strength and ductility, have attracted significant attention by the research community. The incorporation of gradient structures (GSs) further can enhance their mechanical properties. In the present research, we employ the rotation acceleration shot peening technique to introduce a GS within the CoCrNi FCC MEA to investigate underlying mechanisms governing the physical deformation processes during the generation of GSs through processing, which the primary goal is mitigating the intrinsic trade-off between strength and ductility. Through the microstructures analysis along the depth direction, both pre and post uniaxial tensile plastic deformation, we unveiled that the low stacking fault (SF) energy characteristic of the CoCrNi MEA triggered the emergence of diverse defects in the core region. The presence of nanoscale deformation twins, SFs, Lomer–Cottrell dislocation locks and phase transformation from FCC to hexagonal close-packed at twin boundaries synergistically enhanced the strain hardening capacity of the material.

Stereochemical Impacts on Acyclic Mechanochemical Carbon-Carbon Bond Activation.

The influence of stereochemistry on the mechanochemistry rate is studied using a new mechanophore based on a benzopinacol (BP) skeleton. Two sets of BP diastereomers, the meso R,S and the R,R/S,S were isolated, incorporated into the center of a poly(methyl acrylate), and their mechanical activation rate was measured in solution. Under mechanical stress, the central C-C bond in BP is cleaved, providing two independent benzophenone molecules with higher UV-absorption coefficient at 254 nm. Monitoring the reaction rate spectroscopically indicates that the chiral R,R/S,S enantiomers react ~1.4 fold faster compared to the meso R,S diastereomer. In-silico modeling indicates that a hydrogen bond between the syn hydroxyls in the R,R diastereomer becomes shorter with stress, reducing the maximal force required for C-C bond scission, while this bond is inexistent in the meso diastereomer, as the hydroxyl are anti to each other. Our results indicate that in polymer where free rotation around bonds is possible, non-covalent interactions between backbone substituents, which are affected by relative stereochemistry, can play a fundamental role in the mechanochemical stability of the polymer.

Stereochemical Impacts on Acyclic Mechanochemical Carbon‐Carbon Bond Activation

The influence of stereochemistry on the mechanochemistry rate is studied using a new mechanophore based on a benzopinacol (BP) skeleton. Two sets of BP diastereomers, the meso R,S and the R,R/S,S were isolated, incorporated into the center of a poly(methyl acrylate), and their mechanical activation rate was measured in solution. Under mechanical stress, the central C‐C bond in BP is cleaved, providing two independent benzophenone molecules with higher UV‐absorption coefficient at 254 nm. Monitoring the reaction rate spectroscopically indicates that the chiral R,R/S,S enantiomers react ~1.4 fold faster compared to the meso R,S diastereomer. In‐silico modeling indicates that a hydrogen bond between the syn hydroxyls in the R,R diastereomer becomes shorter with stress, reducing the maximal force required for C‐C bond scission, while this bond is inexistent in the meso diastereomer, as the hydroxyl are anti to each other. Our results indicate that in polymer where free rotation around bonds is possible, non‐covalent interactions between backbone substituents, which are affected by relative stereochemistry, can play a fundamental role in the mechanochemical stability of the polymer.

Myocardial single photon emission computed tomography imaging to identify non-responders to cardiac resynchronization therapy in patients with non-left bundle branch block

Abstract Background Non-response to cardiac resynchronization therapy (CRT) is an important issue in the treatment of heart failure with reduced ejection fraction (HFrEF) and non-left bundle branch block (LBBB). Although the QRS duration and morphology are crucial parameters for selecting CRT candidates, electrocardiogram (ECG) markers may inadequately represent the mechanical activation patterns within the heart. Owing to limitations associated with the ECG criteria, there is increasing interest in advanced multimodality imaging to improve patient selection. Recently, myocardial single-photon emission computed tomography imaging (G-MPI) is used for assessing left ventricular (LV) dyssynchrony. This technique is mostly automatic and has high intra- and inter-observer reproducibility and repeatability. Objectives This study aimed to examine whether preoperative G-MPI evaluation could predict non-responsiveness to CRT in patients with HFrEF with non-LBBB. Methods Between January 2021 and December 2022, 128 patients underwent CRT, of whom 73 with pre-operative evaluation using G-MPI were selected. Forty-three patients with non-LBBB (21 and 22 CRT responders and non-responders, respectively) were assessed. These patients were divided into CRT responder and non-responder groups. We evaluated the cut-off and clinical impact of pre-operative G-MPI parameters in predicting non-responsiveness to CRT. In addition, 30 patients with LBBB were analyzed. Results Among patients with non-LBBB, CRT responders and non-responders showed no significant differences in baseline characteristics, except for the LV dimension. A receiver operating characteristic curve analysis identified 108° and 27.7° as the optimal cut-offs for the bandwidth and phase standard deviation (SD), respectively, to predict non-responsiveness to CRT (area under the curve [AUC]=0.762; 95% confidence interval [CI]: 0.601–0.923 and AUC=0.742; 95% CI: 0.576–0.909, respectively). A multivariate analysis revealed that a cut-off bandwidth of ≥108° and phase SD of ≥27.7° are independent predictors of non-responsiveness to CRT in patients with non-LBBB (hazard ratios 5.65; 95% CI: 1.53–20.9; P=0.009). In contrast, there were no relationships between G-MPI parameters and non-responsiveness to CRT in patients with LBBB. Conclusions Pre-operative G-MPI findings were associated with non-responsiveness to CRT in patients with non-LBBB. The identification of potentially nonresponsive patients could influence patient management and alter outcomes.

Magnetic Properties of a Nickel–Zinc Ferrite Powder with Different Degrees of Dispersion

The influence of the degree of dispersion of a nickel–zinc ferrite powder of a Ni0.7Zn0.3Fe2O4 composition on its magnetic properties has been considered. The material has been synthesized using the ceramic technology with preliminary mechanical activation of precursors. The degree of dispersion has been varied using different modes of its dry grinding in a ball mill. The patterns of the changes in saturation magnetization and the coercive force as a function of grinding modes and a specific surface area of the ferrite powder have been established. The changes in the pattern of the magnetic phase transition in the region of the Curie temperature of materials with different degrees of dispersion have been determined.

The Effect of Copper Nanoparticles on Liver Metabolism Depends on the Type of Dietary Fiber.

A diet enriched with copper nanoparticles (CuNPs) exhibits a wide range of effects on liver metabolism, both positive and negative. Dietary fibers are the key components that may affect the absorption of minerals, including copper, and change their impact on organisms. Therefore, this study investigated whether and how supplementation with different sources of dietary fiber (cellulose, pectin, inulin, and psyllium) affects the function of CuNPs in the liver of male Wistar rats. The results showed that CuNPs at different doses had varying effects on lipid metabolism and inflammation in the liver. Specifically, higher doses of CuNPs were associated with increased lipid accumulation and the activation of pro-inflammatory mechanisms. However, combining CuNPs with dietary fibers, such as psyllium and inulin, was beneficial in mitigating the effects of the examined nanoparticles, leading to reduced fat, cholesterol, and triglycerides in the liver. Combining psyllium with CuNPs showed the most substantial effect on liver metabolism and inflammation parameters. Furthermore, hepatic histology analyses showed that adding psyllium to the diet with CuNPs reduces changes associated with fat accumulation and mononuclear cell infiltration. The observed beneficial changes in the liver may have been related to a reduction in the gene expression level of sterol regulatory element-binding protein 1 and peroxisome proliferator-activated receptor gamma and cyclooxygenase-2. In conclusion, enriching the diet with dietary fibers such as psyllium can regulate the action of CuNPs, thereby improving lipid metabolism and reducing inflammation in the liver.

Phenolic compounds and spare carbohydrates content dynamics in seeds of the invasive species Acer negundo and the native species Acer tataricum in connection with their competitiveness in biocenoses

Changes in the content of various phenolic carboxylic acids (FCC) – chlorogenic (HC), caffeic (CC), ferulic (FC), as well as the amounts of flavonoids and spare carbohydrates (monosaccharides, polysaccharides and starch) in the tissues of Acer tataricum and Acer negundo seed embryos (indigenous and invasive species, respectively) during their storage were studied from October to March (cold chamber, t° = +5°C, humidity 80%). There was a significant increase in the content of HC and the absence of CC in December-January in an aboriginal species with a long dormant period. In the invasive species A. negundo, which does not have a rest period, the level of HC also increased, but was ten times lower than in A. tataricum, while a high level of CC was identified. In terms of flavonoid content, the native species A. tataricum is ten times superior to the invasive A. negundo. The carbohydrate content in A. tataricum was about 40%, and in the tissues of A. negundo seed embryos about 15% and did not change during the entire storage period. The dynamics of the content of phenolic compounds and forms of spare carbohydrates, their relationship with the activation of metabolic processes and protective anti-stress mechanisms during the cold storage of seeds and competitiveness in biocenoses are discussed.

CRB2 Depletion Induces YAP Signaling and Disrupts Mechanosensing in Podocytes.

Focal Segmental Glomerulosclerosis (FSGS) is a histologic lesion caused by a variety of injurious stimuli that lead to dysfunction/loss of glomerular visceral epithelial cells (i.e. podocytes). Pathogenic mutations in CRB2, encoding the type 1 transmembrane protein Crumb 2 Homolog Protein, have been shown to cause early-onset corticosteroid-resistant nephrotic syndrome (SRNS)/FSGS. Here, we identified a 2-generation East Asian kindred (DUK40595) with biopsy-proven SRNS/FSGS caused by a compound heterozygous mutation in CRB2 comprised of the previously described truncating mutation p.Gly1036_Alafs*43 and a rare 9-bp deletion mutation p.Leu1074_Asp1076del. Because compound heterozygous mutations involving the truncating p.Gly1036_Alafs*43 variant have been associated with reduced CRB2 expression in podocytes and autosomal recessive SRNS/FSGS, we sought to define the pathogenic effects of CRB2 deficiency in podocytes. We show that CRB2 knockdown induces YAP activity and target gene expression in podocytes. It upregulates YAP-mediated mechanosignaling and increases the density of focal adhesion and F-actin. Using Elastic Resonator Interference Stress Microscopy (ERISM), we demonstrate that CRB2 knockdown also enhances podocyte contractility in a substrate stiffness-dependent manner. The knockdown effect decreases with increasing substrate stiffness, indicating impaired mechanosensing in CRB2 knockdown cells at low substrate stiffness. While the mechanical activation of CRB2 knockdown cells is associated with increased YAP activity, the enhanced cell contractility is not significantly reduced by the selective YAP inhibitors K-975 and verteporfin, suggesting that multiple pathways may be involved in mechanosignaling downstream of CRB2. Taken together, these studies provide the first evidence that CRB2 deficiency may impair podocyte mechanotransduction via disruption of YAP signaling in podocytes.

Molecular insights into Solanum sisymbriifolium’s resistance against Globodera pallida via RNA-seq

BackgroundThe presence of potato cyst nematodes (PCN) causes a significant risk to potato crops globally, leading to reduced yields and economic losses. While the plant Solanum sisymbriifolium is known for its resistance to PCN and can be used as a trap crop, the molecular mechanisms behind this resistance remain poorly understood. In this study, genes differentially expressed were identified in control and infected plants during the early stages of the S. sisymbriifolium - G. pallida interaction.ResultsGene expression profiles were characterized for two S. sisymbriifolium cultivars, Melody and Sis6001, uninfected and infected by G. pallida. The comparative transcriptome analysis revealed a total of 4,087 and 2,043 differentially expressed genes (DEGs) in response to nematode infection in the cultivars Melody and Sis6001, respectively. Gene ontology (GO) enrichment analysis provided insights into the response of the plant to nematode infection, indicating an activation of the plant metabolism, oxidative stress leading to defence mechanism activation, and modification of the plant cell wall. Genes associated with the jasmonic and salicylic acid pathways were also found to be differentially expressed, suggesting their involvement in the plant’s defence response. In addition, the analysis of NBS-LRR domain-containing transcripts that play an important role in hypersensitive response and programmed cell death led to the identification of ten transcripts that had no annotations from the databases, with emphasis on TRINITY_DN52667_C1_G1, found to be upregulated in both cultivars.ConclusionsThese findings represent an important step towards understanding the molecular basis underlying plant resistance to nematodes and facilitating the development of more effective control strategies against PCN.

A Review of the Utilization of Recycled Powder from Concrete Waste as a Cement Partial Replacement in Cement-Based Materials: Fundamental Properties and Activation Methods

Recycled powder (RP) is the primary by-product generated during the reclamation process of construction and demolition waste (CDW). There is existing literature on the use of RP as supplemental cementitious materials (SCMs) in cement-based materials, but a comprehensive evaluation on the characteristics of RP generated from concrete waste has been missing until now. This paper critically reviews the use of RP from concrete waste in cement-based materials, as concrete waste makes up a significant amount of CDW and other components have designated recycling methods. In this sense, this study conducted a critical analysis on the use of RP as an SCM, using detailed literature research. The technology used for producing RP is detailed along with its chemical, mineralogy, and microstructural characteristics. Fresh-state properties in cementitious matrices with RP are introduced with the view of mechanical grinding, thermal activation, carbonation, chemical treatment, biomineralization, mineral addition, nano activation, and carbonation. The review highlights the significant potential of utilizing RP in cement-based materials. Specifically, RP can be advantageously utilized in the production of value-added construction materials.

Facile construction of a stable biomass-derived carbon-supported Al[sbnd]Zr composite with crystalline solid solution and Brønsted–Lewis dual acidity for efficient catalytic conversion of cellulose

Exploiting cellulose-derived levulinic acid (LA) in biorefinery has potential application prospects, and the development of efficient and stable catalysts is crucial yet challenging. In this study, a bimetallic synergy strategy was proposed to construct an efficient and durable solid acid catalyst with crystalline solid solution by a totally solid-phase method. Mechanical activation (MA)-treated precursor (metal salts, starch, and urea) was calcined to obtain a stable biomass-derived carbon (BC)-supported AlZr (MA-AZ/BC) composite, which was applied for catalytic conversion of cellulose to LA in aqueous-phase system. The results indicate that the synergistic effect of bimetallic crystalline solid solution and the existence of Brønsted–Lewis dual-acid sites in the MA-AZ/BC catalyst contributed to a cellulose conversion efficiency of 97.5 % and a LA yield of 67.1 %. Benefiting from the strong bimetal–support interaction, the MA-AZ/BC catalyst exhibited favorable stability and recoverability. On the basis of comprehensive analysis, a reaction mechanism of Brønsted–Lewis dual-acid sites for synergistic catalytic conversion of cellulose was proposed. This study provides a new idea for the rational design and environmentally friendly fabrication of functional BC-based catalysts for efficiently producing platform compounds derived from biomass.

Study of special adaptation mechanisms and morphological regularities of broiler chickens against the background of pharmacological prevention combined pre-slaughter, heat and transport stress in industrial poultry farming

The study was conducted to investigate the adaptation mechanisms of broiler chickens against the background of pharmacological prevention which includes combined pre-slaughter, heat and transport stress in industrial poultry farming. In summer, from clinically healthy Ross 308 chickens three groups of 95648 ± 931 chickens were formed on the principle of analogy. The first group was a control group and it was fed with complete feed. The second group was the first experimental group and it was fed with complete feed which included the anti-stress supplementary feed PIK-antistress at a dose of 1270 g per 1 ton of feed 5 days before slaughter. The third group was the second experimental group and it was fed with the anti-stress supplementary feed PIK-antistress which included L-carnitine at a dose of 1700 g per 1 ton of feed 5 days before slaughter. 38 days later broiler chickens were slaughtered. 3 main periods were commonly studied: the period after fasting, the period after transporting the chickens to the slaughter site and the period just before slaughter. Adaptation processes were developing during the slaughter of broiler chickens in summer. The processes are characterized by increasing the level of the ratio of heterophils to blood lymphocytes on average 2.8 times. The use of the complex food additive PIK-antistress and PIK-antistress in combination with L-carnitine can reduce the activity of stress-implementing mechanisms and increase the survivability of chickens by 3.20 and 4.58 %, respectively and the European productivity index by 32 and 45 units. All the data obtained are consistent with the morphometric studies of the adrenal glands while against the background of the use of anti-stress prophylaxis an increase of core area was noted by 43.0 % and 36.0 % and respectively against the background of a decrease of the area of the cytoplasm of the cortical cords by 11.2 % and 22.8 %, respectively, which indicates stabilization of metabolic processes in the cell.

Olaparib: A Chemosensitizer for the Treatment of Glioblastoma.

Glioblastoma (GBM) is the most prevalent and deadly primary brain tumor. The current treatment for GBM includes adjuvant chemotherapy with temozolomide (TMZ), radiation therapy, and surgical tumor excision. There is still an issue because 50% of patients with GBM who get TMZ have low survival rates due to TMZ resistance. The activation of several DNA repair mechanisms, such as Base Excision Repair (BER), DNA Mismatch Repair (MMR), and O-6- Methylguanine-DNA Methyltransferase (MGMT), is the main mechanism via which TMZ resistance develops. The zinc-finger DNA-binding enzyme poly (ADP-ribose) polymerase-1 (PARP1), which is activated by binding to DNA breaks, affects the activation of the MGMT, BER, and MMR pathway deficiency, which results in TMZ resistance in GBM. PARP inhibitors have been studied recently as sensitizing medications to increase TMZ potency. The first member of the PARP inhibitor family to be identified was Olaparib. It inhibits PARP1 and PARP2, which causes apoptosis in cancer cells and DNA strand break. Olaparib is currently investigated as a radio- and/or chemo-sensitizer in addition to being used as a single agent because it may increase the cytotoxic effects of other treatments. This review addresses Olaparib and its significance in treating TMZ resistance in GBM.

Activation of Secondary Metabolism and Protease Activity Mechanisms in the Black Koji Mold Aspergillus luchuensis through Coculture with Animal Cells.

The activation of secondary metabolism plays a pivotal role in the discovery of novel natural products. We recently developed a coculture method involving actinomycetes and mouse macrophage-like cells to stimulate the production of bioactive compounds. A black koji mold, Aspergillus luchuensis IFM 61405, markedly enhanced the production of (3S,8R)-8-hydroxy-3-carboxy-2-methylenenonanoic acid (1a), (3S,8S)-8-hydroxy-3-carboxy-2-methylenenonanoic acid (1b), and (3S)-9-hydroxy-3-carboxy-2-methylenenonanoic acid (2) when coincubated with J774.1 mouse macrophage cells. The production of 1 and 2 increased by at least 3.5-fold and 2.7-fold, respectively, compared to monoculture after 7 days. A mechanistic investigation revealed that a protease from strain IFM 61405 plays a key role in enhancing the production of 1 and 2. This enhancement was not replicated in A. niger IFM 59706, a nonkoji mold, despite the presence of biosynthetic genes for 1 and 2 in A. niger IFM 59706. Furthermore, the addition of protease inhibitors suppressed the production of 1 and 2, suggesting that proteins secreted from animal cells, likely degraded by proteases secreted by strain IFM 61405, serve as precursors for 1 and 2. The results show that the strategy of coculturing koji mold with animal cells has the potential to enhance the production of natural products.

Spatiotemporal Analysis of Complex Emission Dynamics in Port Areas Using High-Density Air Sensor Network.

Cargo terminals, as pivotal hubs of mechanical activities, maritime shipping, and land transportation, are significant sources of air pollutants, exhibiting considerable spatiotemporal heterogeneity due to the complex and irregular nature of emissions. This study employed a high-density air sensor network with 17 sites across four functional zones in two Shanghai cargo terminals to monitor NO and NO2 concentrations with high spatiotemporal resolution post sensor data validation against regulatory monitoring stations. Notably, NO and NO2 concentrations within the terminal surged during the night, peaking at 06:00 h, likely due to local regulations on heavy-duty diesel trucks. Spatial analysis revealed the highest NO concentrations in the core operational areas and adjacent roads, with significantly lower levels in the outer ring, indicating strong emission sources and limited dispersion. Employing the lowest percentile method for baseline extraction from high-resolution data, this study identified local emissions as the primary source of NO, constituting over 80% of total emissions. Elevated background concentrations of NO2 suggested a gradual oxidation of NO into NO2, with local emissions contributing to 32-70% of the total NO2 concentration. These findings provide valuable insights into the NO and NO2 emission characteristics across different terminal areas, aiding decision-makers in developing targeted emission control policies.

Salinity influence on Mytilus galloprovincialis exposed to antineoplastic agents: a transcriptomic, biochemical, and histopathological approach

Nowadays, aquatic species face a variety of environmental risks associated with pharmaceutical consumption. More specifically, the increased number of cancer patients has been accompanied by an increased consumption of antineoplastic drugs, such as ifosfamide (IF) and cyclophosphamide (CP). These drugs have been found in aquatic ecosystems, raising concerns about their impact, especially on estuarine species, as marine waters are the final recipients of continental effluents. Simultaneously, predicted climatic changes, such as salinity shifts, may threaten organisms. Considering this, the present research aims to investigate the combined effects of IF and CP, and salinity shifts. For this, a transcriptomic, biochemical, and histopathological assessment was made using the bivalve species Mytilus galloprovincialis exposed for 28 days to IF and CP (500 ng/L), individually, at different salinity levels (20, 30, and 40). IF and CP up-regulated metabolism-related gene cyp3a1, with CP also affecting abcc gene, showing minimal salinity impact and highlighting the importance of these metabolic routes in mussels. Salinity shifts affected the transcription of genes related to apoptosis and cell cycle growth, such as p53, as well as the aerobic metabolism, the antioxidant and biotransformation mechanisms. These findings indicate mussels' high metabolic adaptability to osmotic stress. Under CP exposure and low salinity, mussels exhibited increased cellular damage and histopathological effects in digestive gland tubules, revealing detrimental effects towards M. galloprovincialis, and suggesting that a metabolic slowdown and activation of antioxidant mechanisms helped prevent oxidative damage at the control and high salinities. Overall, results reinforce the need for antineoplastics ecotoxicological risk assessment, especially under foreseen climate change scenarios.

Calcium ATPase (PMCA) and GLUT-4 Upregulation in the Transverse Tubule Membrane of Skeletal Muscle from a Rat Model of Chronic Heart Failure.

Intolerance to exercise is a symptom associated with chronic heart failure (CHF) resulting in SM waste and weakness in humans. The effect of CHF on skeletal muscle (SM) arose from experimental evidence in rat models to explain the underlying mechanism. We investigated SM mechanical and metabolic properties in sham rats and with coronary ligation-induced CHF. After twelve weeks of CHF, rats were catheterized to measure right auricular pressure, SM mechanical properties, SERCA-ATPase activity and plasma membrane Ca2+-ATPase (PMCA) hydrolytic activity in isolated sarcoplasmic reticulum (SR) and transverse tubule (TT membrane), respectively, in the sham and CHF. The right auricular pressure and plasma nitrite concentration in CHF increased two-fold with respect to the sham. Pleural effusion and ascites were detected in CHF, confirming CHF. SERCA activity was conserved in CHF. In TT membranes from CHF, the glucose transporter GLUT4 increased seven-fold, and the PMCA hydrolytic activity increased five-fold, but in isolated muscle, the mechanical properties were unaffected. The absence of a deleterious effect of coronary ligation-induced CHF in the rat model on SM could be explained by the increased activity of PMCA and increased presence of GLUT-4 on the TT membrane, which may be involved in the mechanical outcome of the EDL.

New Catalytic Residues and Catalytic Mechanism of the RNase T1 Family.

The ribonuclease T1 family, including RNase Po1 secreted by Pleurotus ostreatus, exhibits antitumor activity. Here, we resolved the Po1/guanosine-3'-monophosphate complex (3'GMP) structure at 1.75 Å. Structure comparison and fragment molecular orbital (FMO) calculation between the apo form and the Po1/3'GMP complex identified Phe38, Phe40, and Glu42 as the key binding residues. Two types of the RNase/3'GMP complex in RNasePo1 and RNase T1 were homologous to Po1, and FMO calculations elucidated that the biprotonated histidine on the β3 sheet (His36) on the β3 sheet and deprotonated Glu54 on the β4 sheet were advantageous to RNase activity. Moreover, tyrosine (Tyr34) on the β3 sheet was elucidated as a crucial catalytic residues. Mutation of Tyr34 with phenylalanine decreased RNase activity and diminished antitumor efficacy compared to that in the wild type. This suggests the importance of RNase activity in antitumor mechanisms.

A classification and recognition model for multiple fruit tree leaf diseases

Abstract Fruit tree leaf diseases affect both fruit survival rate and orchard revenue. Rapid and accurate identification of tree leaf diseases not only prevents the spread of diseases but also ensures healthy tree growth and improves fruit quality. Existing models mostly focus on individual types of tree leaf diseases, with limited applications in the identification of multiple tree leaf diseases. In response to the insensitivity of current classification models to disease region features and the issue of increased error rates due to the presence of similar diseases, this study proposes a residual network model based on the ECA channel attention mechanism and meta-Acon adaptive activation function.The model employs ResNet34 as the backbone network and incorporates the ECA module after each residual block to focus on relevant information. Additionally, a new activation function called meta-Acon is introduced to enhance the model's generalization ability through its dynamic learning capability. Finally, the model's recognition performance is improved by fusing bottom-level features with features from other layers using the Feature Pyramid Network (FPN).Experimental results on a dataset augmented with Mosaic processing show that the FPEM-ResNet34 model achieves a classification accuracy of 98.46%. Compared to other common models such as VGG-16, Inception-V1,AlexNet, and ResNet50, the proposed method mentioned in this paper demonstrates more effective improvement in the accuracy of tree leaf classification, making it highly valuable for practical applications..

The effect of cobalt content and mechanical activation on combustion in the Ni + Al + Co system

The effect of mechanical activation (MA) and cobalt content on the combustion velocity and maximum combustion temperature, elongation of samples during synthesis, the size of composite particles of the mixture after MA, phase composition and morphology of combustion products in the Ni + Al + Co system is investigated in this work. Activation of the Ni + Al + xCo mixture allowed the samples to burn at room temperature, with a cobalt content of up to 50 wt. %. An increase in the cobalt content in Ni + Al + xCo mixtures led to a decrease in the size of composite particles after MA, elongation of product samples and the maximum synthesis temperature. After MA, the elongation of the product samples and combustion velocity increased many times, the maximum synthesis temperature increased. With an increase in the cobalt content in the Ni + Al + Co mixture, combustion velocity first increases (at 10% Co), then decreases. Solid solutions based on NiAl and Ni3Al intermetallides were synthesized by the SHS method.